Hermetic pumps for use in refrigeration systems



Dec. 8, 1959 L. H. LEONARD, JR

HERMETIC PUMPS FOR USE IN REFRIGERATION SYSTEMS Filed July 8, 1957 2Sheets-Sheet 1 0000 0000 ooo8 oo OOOOOOOOOOO 0000000000 INVENTOR. LOUISH. LEONARD, JR. BY WJ'M FIG.

ATTORNEY.

HERMETIC PUMPS FOR USE IN REFRIGERATION SYSTEMS Filed July 8. 1957 Dec.8, 1959 L. H. LEONARD, JR

2 Sheets-Sheet 2 FIG. 3

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ATTORNEY.

United States Patent HERIVIETIC PUMPS FOR USE IN REFRIGERATION SYSTEMS"15 Claims. (Cl. 62494) N.Y., assignor to a corporation of Thisinvention relates to absorption refrigeration systems and, moreparticularly, to pumps for use in absorption refrigeration systems forcirculating solution.

In absorption refrigeration systems of the type disclosed in my PatentNo. 2,722,805, granted November 8, 1955, employing saline solutions suchas a mixture of water and lithium bromide as an absorbent and water as arefrigerant, in which the system operates with a minimum practicalamount of air leakage, I have found that metal plating such as copperplating occurs in many parts of the system, particularly on moving partssuch as pump seal faces, pump bearings, etc. The phenomenon is not fullyunderstood but it is believed that lithium bromide dissolves smallamounts of copper from the cuprinickel or copper elements employed inthe system which are exposed to solution. After limited solubility isreached, it is believed the metal plates out in the form of pure copper.The phenomenon does not appear to occur in systems which aresubstantially air tight so that oxygen is not present in the system. Inspite of the use of many different types of material for bearings, ithas been found that the pump bearings soon seized as a result of platingon the bearing surfaces.

Many attempts have been made to solve the problem by isolating the pumpand motor bearings from solution. For example, it has been suggestedthat mercury seals be employed, that very long shafts be employed in anattempt to locate the motor and bearings above the solution level, thatinternal pump seals be used which would permit the motor and bearings tooperate in water or octyl alcohol, etc. However, all of these variousarrangements present serious problems, the most important problemresiding in the fact that under certain circumstances, it is impossibleto prevent solution from contacting the bearings of the pump.

The present invention solves the problem of metal plating by acceptingthe fact and providing a pump structure which automatically moves one ofthe cooperating bearing surfaces away from the other while continuingoperation of the pump thereby preventing seizure of the bearing andfailure of the pump.

The chief object of the present invention is to provide an absorptionrefrigeration system including a pump structure for circulating solutionso designed that the usual metal plating of the bearing structure duringoperation of the system will not interfere with operation of the pump.

An object of the present invention is to provide a pump for use in alocation in which it is exposed to a metal plating action such as anabsorption refrigeration system employing a salt solution as anabsorbing medium so designed that as metal plating occurs, the rotatingassembly of the pump will move upward away from the stationary membersof the structure thus maintaining a desired clearance between thecooperating surfaces of the bearing structure to prevent seizure of thebearing.

A further object is to provide a method of operation of an absorptionrefrigeration system. Other objects of the ice invention will be readilyperceived from the following description.

This invention relates to an absorption refrigeration system whichcomprises, in combination, an absorber, an evaporator, vapor from theevaporator flowing to the absorber to be absorbed by solution therein, acondenser, a generator, vapor from the generator flowing to thecondenser to be condensed therein, condensate from the condenser passingto the evaporator, and means to circulate solution, said meanscomprising a pump assembly including a pump housing having an inlet andan outlet, an impeller in said housing, a motor for actuating saidimpeller, a shaft carrying said impeller and connected to said motor, abearing supporting the shaft in desired position to permit rotationthereof, the bearing including a fixed member and a movable member, oneof said members having a tapered surface whereby upon plating of thebearing the movable member of the bearing tends to move in a directionaway from the impeller housing.

This invention further relates to a pump for use in a location in whichit is exposed to a metal plating action such as an absorptionrefrigeration system employing a salt solution as an absorbing mediumcomprising, in combination, a pump housing having an inlet and anoutlet, an impeller in said housing, a motor for actuating saidimpeller, a shaft carrying said impeller and connected to said motor, abearing supporting the shaft in desired position to permit rotationthereof, the bearing including a fixed member and a movable member, oneof said members having a tapered surface whereby upon plating of thebearing the movable member of the bearing tends to move in a directionaway from the impeller housing.

This invention further relates to a method of operation of an absorptionrefrigeration system employing a pump for circulating solution in whichthe solution is capable of metal plating the bearing surfaces of thepump, the steps consisting in rotating the pump impeller to circulatesolution, and, as plating of the bearing surfaces occurs, automaticallymoving one of the cooperating bearing surfaces to prevent seizure of thebearing and failure of the pump.

The attached drawings illustrate a preferred embodiment of the presentinvention, in which Figure 1 is a flow diagram of an absorptionrefrigeration system including the pump structure of the presentinvention;

Figure 2 is a sectional view of the pump structure;

Figure 3 is a fragmentary sectional view of an absorber shell modifiedto receive the improved pump structure;

Figure 4 is a fragmentary sectional view of a modified bearingstructure; and

Figure 5 is a fragmentary sectional pump assembly.

Referring to the attached drawings, there is illustrateddiagrammatically in Figure 1 the absorption refrigeration system of thepresent invention. The system comprises a shell 2, containing aplurality of tubes 3, which cooperate with the shell to form anabsorber. Placed in shell 2 above absorber 3 is a pan-like member whichcooperates with shell 2 to form an evaporator 4. A plurality of tubes 5extend longitudinally of the shell above the pan-like member. Medium tobe cooled passes through these tubes in heat exchange relation withliquid refrigerant sprayed thereover. A vapor condensate return header 6is placed over the tubes 5 and serves to discharge condensate thereover.

A second shell 7, preferably, is placed above the first shell. Tubes 8extend in the power portion of shell 7 and cooperate with shell 7 toform a generator. A plurality of tubes 9 are placed in the upper portionof shell 7 to form a condenser. The tubes 9 cooperate with a pan-likemember 10 to form the condenser. Both shells view of a modified tion maybe discharged in stantially constant.

3. are, supported in desired position on supports (not shown).

Pump 11 withdraws weak solution from absorber 3 through line 12. Pump'11 forwards weak solution through line 13 to heat exchanger 14 in whichthe weak solution'is placed in heat. exchange'relation with strongsolution returning from the generator as hereinafter de-' scribed. Theweak solution is then forwarded from heat exchanger 14 through line 15to generator '8. Strong solution flows from generator'8 through overflowarrangement 16, line 17, heat exchanger 14, and line 18 to the absorber,preferably, being discharged therein adjacent one end of shell 2. Strongsolution flows through forces of gravity from the genator to theabsorber. It will be understood, or" course, if desired, the strong'solu the absorber over the tubes of solution'through the generator issub- The specific construction of pump 11 is hereinafter described.

Pump 19 serves as an absorber pump and is employed to withdraw asolution of intermediate concentration from absorber 3 through line 21.The specific construction of pump 19 is hereinafter described.Preferably, pump 19 is enclosed in the absorber shell; the solution ofintermediate concentration through line 22 to the absorber. Sprayarrangement 23 serves to distribute the recirculated solution over thetubes throughtherein. Flow out the length of the absorber 3. It will beunderstood that the strong solution mixes to some extent with'solutionin the absorber and that further mixing occurs as the pump 19 forwardsthe tion having a concentration intermediate the concentra- Pump 19forwards mixed solution so that a solution of the strong and weaksolutions is circulated.

Reference is made to co.pending application, Serial No. 505,369, filedApril 8, 1955, now Patent No. 2,840,977 in the name of Louis H. Leonard,Jr., for a more detailed description of the flow of solution in thesystem.

Condensing water is forwarded by a pump (not shown) through line 25 tothe tubes3 of the absorber. The condensing water passes from the tubes 3of theabsorber through line 26 to the tubes 9 of the condenser.Condensing water leaves the tubes 9 of the condenser through line 27.

A modulating valve 29 is placed in line 27 to regulate flow ofcondensing water through the condenser. Valve 29 is actuated in responseto the temperature of chilled medium leaving the evaporator. A suitablecontrol system is disclosed and claimed in my Patent No. 2,722,805,granted November 8, 1955. Under some circumstances, if desired, a bypassline 27 may be provided about the condenser, a manual valve 27" beingplaced in line 27'. Line 27 permits an initial adjustment of the flow ofcondensing water through the condenser so that the proper condensingtemperature is maintained for full load operation.

Medium to be cooled is forwarded by a pump (not shown) through line 30to the tubes of coil 5 of evalporator 4. The cooled medium leaves thetubes S-through line 31 and is forwarded to a place of use such as thecentral station of an air conditioning system. The medium, after passingthrough the central station, returns to the evaporator 4 through line 30to be againcooled and reused.

Condensate leaves condenser 9 returned to header 6 in the evaporator anddischarged in the evaporator over the tubes 5 to wet. thetubes. It willbe appreciated the refrigerant is flashed or vapor ized to cool the sameupon its discharge in the evaporator and is vaporized by its heatexchange relation with medium passing through the tubes of theevaporator. The flashed vapor passes to absorber '3 to be absorbed bythe solution therein.

Pump 35 serves to recirculate liquid refrigerant collected in theevaporator. evaporator by line 36 through line 32 and isneed forsolution pump seals.

. 110 and a movable member 111 secured to the shaft104.

. the impeller greater I the impeller so'that Pump 35 isconnected tothe'to withdraw liquid refrigerant aerasae therefrom. Pump 35 forwards theliquid refrigerant through line 37 to spray arrangement 38 of theevaporator, the liquid refrigerant flash cooling upon discharge in theevaporator, remaining liquid refrigerant wetting the tubes to coolmedium passing through the tubes. The heat exchange relation betweenmedium passing through the tubes and the liquid refrigerant on theexterior of the tubes cools the medium and evaporates the liquidrefrigerant. The vapor passes to the absorber as previously described. 7

A suitable purge arrangement indicated generally at 42 is provided toremove non-condensible gases from I the absorber. The ejector 43 ofpurge arrangement 42 is connected by line 44 to a purgeline 45 extendinglongitudinally of the absorber. 'The cooling coil 46 of purgearrangement 42 is connected to line 30 by line 46' and to line 31 byline 47, permitting medium to be employed for cooling solution in thepurge tank 48. The purge arrangement 42 is disclosed and claimed in co-=pending-application, Serial No. 565,324, filed February 14, 1956, in thename of Louis H. Leonard, Jr., and reference is made to such applicationfor a more complete description of the purging arrangement.

A more detailed description of the absorber and the evaporator aredisclosed and claimed in co-pending application Serial No. 580,052,filed February 3, 1956, in the name of Louis H. Leonard, Jr.

Steam is supplied to the generator through line 51 and is condensed inthe tubes of the generator 8 in heat exchange relation with solution inthe generator, the condensate leaving the generator through line 52, asteam trap 53 being placed in line 52.

The preferred absorbing solution is a solution of lithium bromide andwater. The preferred refrigerant is water. Preferably, the solutionconcentration leaving the generator is about 66%. As stated above, agreater concentration may permit crystallization to occur, causingsolidification in the heat exchanger and perhaps in other portions ofthe system.

The term weak solution is used herein to describe a solution weak inabsorbing power. The term strong solution is used'herein to define asolution strong in absorbing power.

As shown in Figure 1, absorber pump 19, preferably, is placed in theabsorber shell in a position in which at least the greater portion ofthe pump assembly is surrounded by solution in the absorber thus'eliminating the Absorber pump 19 (refer to Figure 2) includes a housinghaving an inlet} 101 and an outlet 102. An impeller 103 is placed inthehousing 100 and is carried by a vertically extending shaft} 104connected to the rotor 105 of a motor 106. When the motor is stopped,forces of gravity keeps the assembly located properly. On start-up,thrust pulls the assem-' bly downward, maintaining the cooperatingbearing sur faces hereinafter described in contact with each other. Itwill be appreciated the motor stator and rotor are encased in a materialresistant to the solution such as an epoxy resin.

Bearings 107 and 108 are provided to support the shaft position in asubstantially vertically extending direc- 109 sup- 1n tion ashereinafter explained. Support members port the bearings 107, 108 andthe motor in the assembly.

Each of the bearings 107, 108 includes a fixed member The cooperatingsurfaces 112, 113 of members 110, 111 are tapered, as shown in Figure 2,themovable member. 111 having an area at its end away from the impellergreater than the area at its end adjacent the impeller."

110 has an area at its end adjacent The fixed member 7 than its area atthe 'end away from pered surfaces during operation of the absorptionrefrigeration system the movable member and shaft carry-.1

106 in position upon plating of the cooperating ta-.

ing the impeller tend to ride upward or to move in a direction away fromthe impeller housing carrying the impeller closer to the upper wall ofthe housing. In other words, the movable member in effect is in the formof a cone or, preferably, the frustum of a cone so placed that itssmaller end is adjacent the housing. The impeller, shaft, movablebearing member and motor rotor form a movable assembly which is pulleddownward by the thrust of the impeller in operation, the assembly movingupward upon plating of the cooperating surfaces of the bearings. It willbe appreciated that under some circumstances wear of the fixed member110 or the movable member 111 may occur due, of course, to length oftime the bearing is in use. Under these circumstances, upon wear of thecooperating surfaces, the movable member 111 tends to move downward orin a direction toward the impeller housing to assure desired clearancebetween the cooperating surfaces of the bearing structure.

A line 115 connected to the discharge of the impeller 103 communicatesby lines 116, 117 with the cooperating surfaces of the bearings thusproviding solution between the cooperating surfaces to lubricate thesame. Suitable wear rings 118, 119 are provided about the shaft andimpeller to seal the housing. I have found that the copper platingdeposits or plates substantially uniformly on all rubbing surfaces sothat the cooperating surfaces 112, 113 at least are uniformly platedduring operation of the system.

While I have described the absorber pump 19 as being of a desiredconstruction, it will be appreciated pump 11 likewise exposed tosolution may be constructed similarly. If desired, all pumps in thesystem exposed to solution may be so constructed. Under somecircumstances, pump 11 and pump 19 may be combined as a single pump forsupplying weak solution to the generator and for recirculating solutionin the absorber.

In Figure 3, I have shown a modification of the invention. In this casethe shell of the absorber is provided with a sump 125 which extendsbelow the shell. Pump assembly 19 is placed in sump 125 below the coilbundle or tubes 3. It will be noted generally that the solution level inthe sump 125 is below the motor 106 so that the bearings 107 operate ina pool of solution. Drops of cooled solution spray or drip from thetubes 3 over motor 106 thus cooling the motor; it will be appreciatedthat the coolest solution in the system is thus employed to cool thepump motor. Since the bearings 107 operate in a pool of solution, it isnot necessary usually to provide lines connecting the outlet of theimpeller with the bearings for lubrication purposes.

In Figure 4, I have shown the movable member 111 of bearing 107 providedwith an extended surface 126. This may be of value during operation ofthe system over a long period of time for it assures that adequatecontacting surfaces are provided even when the movable assembly of thepumps has moved upward a substantial distance.

In Figure 5, I have shown means for raising the stator of the motor whenthe rotor moves upwardly which may be desirable in certain types ofmotors due to the magnetic center of the motor. A yoke 130 is placedabout the shaft 104 between rings 131. A rod 132 carrying yoke 130 isfulcrumed at 133 and is connected by suitable linkage 134 to a rod 135fulcrumed at 136 carrying a support 137 for the stator 106. Thus, as theshaft 104 carrying rotor 105 moves upward, through rods 132, 135 andlinkage 134, stator 106' similarly moves upward thus maintaining themagnetic center of the motor.

In operation, the system is started, pump 19 recirculating solution inthe absorber. Refrigeration is provided by chilling medium passingthrough the tubes of the evaporator. During continued operation, thebearing surfaces of the pump are copper plated. As the cooperatingsurfaces of members 110, 1511 are plated, member 111 6 together withshaft 104, rotor 105 of the motor and impeller 103 automatically moveupward bringing the impeller closer to the top wall of housing andthereby preventing seizure of the bearings and failure of the pump.

The present invention eliminates an extremely difficult problem inabsorption refrigeration systems employing a saline solution as anabsorbent and water as a refrigerant by taking advantage of the factthat uniform metal plating occurs on the rubbing surfaces of the pumpbearings exposed to the absorbent. Preferably, the bearings areconstructed of a material which will be plated easily by copper thuspermitting lubrication of the bearings with the solution and cooling ofthe pump motor by solution. Since the pump thrust pulls down the entireassembly, it will be appreciated the cooperating surfaces of the bearingrest on one another and as such surfaces are plated the movable pumpassembly members are moved upward automatic lly thereby preventingseizure of the bearings.

An extremely simple, economical pump assembly is provided by takingadvantage of What at first glance appears to be an inherent defect ofthe system and turning such defect into an advantage which permitseconomies in construction of the system to be effected and eliminatesthe disadvantages heretofore deemed inherent in the use of pumps in thesystem.

The present invention eliminates the solution pump seal problem whichconfronted the industry since it does not attempt to prevent solutionfrom contacting the pump bearings or it is necessary to provide theexpensive mechanical seals, seal water assemblies and make-up waterlines, etc. heretofore employed. The operation of the system is morequiet for motor noises are confined in the system and are muflled by thewalls of the shell and solution.

While I have described a preferred embodiment of the invention it willbe understood that the invention is not limited thereto since it may beotherwise embodied within the scope of the following claims.

I claim:

1. In a pump for use in a location in which it may be exposed to a metalplating action such as an absorption refrigeration system employing asalt solution as an absorbing medium, the combination of a pump housinghaving an inlet and an outlet, an impeller in said housing, means foractuating said impeller, a shaft carrying said impeller and connected tosaid actuating means, a bearing supporting the shaft in desired positionto permit rotation thereof, the bearing including a fixed member and amovable member, one of said members having a tapered surface wherebyupon wear of the bearing during operation the movable member moves tomaintain a desired clearance with the fixed member while upon plating ofthe bearing during operation the movable member of the bearing tends tomove in a direction away from the impeller housing.

2. In a pump for use in a location in which it is exposed to a metalplating action such as an absorption refrigeration system employing asalt solution as an absorbing medium, the combination of a pump housinghaving an inlet and an outlet, an impeller in said housing, means foractuating said impeller, a shaft carrying said impeller and connected tosaid actuating means, a bearing supportingthe shaft in desired positionto permit rotation thereof, the bearing including a fixed member and amovable member secured to the shaft, said members having cooperatingtapered surfaces whereby upon plating of the bearing during operation ofthe system the shaft and movable member tend to move in a direction awayfrom the impeller housing carrying the impeller closer to a wall of thehousing.

3. In a pump for use in a location in which it is exposed to a metalplating solution such as an absorption re frigeration system employing asalt solution as an abher having an area I greater than the area at theend adjacent the impeller, the fixed member having an area at its endadjacent the sorbing medium, the combination of a pump housing impellergreater than the area at the end away from the impeller whereby uponplating of the cooperating tapered surfaces during operation the shaftand movable member tend to move in a direction away from the impellerhousing carrying the impeller closer to a wall of the housing.

4. In a pump for use in a location in which it is exposed to a metalplating solution such as an absorption re- 'rrigeration system employinga salt solution as an ab-- sol-hing medium, the combination of a pumphousing having an inlet and an ing, a motor for actuating said impeller,a shaft carrying said impeller and connected to said motor, means forsupporting the bearing member and the motor, the bearing memberincluding a stationary member held in substantially fixed position and arotating member secured to said shaft, said membershaving cooperatingsurfaces, the cooperating surface of the rotating member being taperedand the rotating member having a diameter at its end away from theimpeller greater than the diameter of its end adjacent the impellerwhereby upon plating of the cooperating surfaces during operation the'rotat move in a direction away ing member and shaft tend to from theimpeller housing.

5. A pump according to claim 4 including means to supply medium from theimpeller to the cooperating bearing surfaces to lubricate the same,

6. In a pump for use in a location in which it is exposed to a metalplating action such as an absorption refrigeration system employingasalt solution as an absorbing medium, the combination of a pump housinghaving an inlet and an outlet, an impeller in said housm verticallyextending shaft carrying said impeller and connected to said motor, abearing supporting the shaft in substantially'vertical position topermit rotation thereof, the bearing including a fixed member and amovable member secured to the shaft, said members having cooperatingtapered surfaces whereby upon plating of the bearing during operationthe shaft and movable member tend to move in a vertical direction fromthe housing.

7. In a pump for use in a location in which it may be exposed to a metalplating action such as an absorption refrigeration system employing asalt solution as an absorbing medium, the combination of a pump housinghaving an inlet and an outlet, an impeller in said housing, a motor foractuating said impeller, a shaft carrying said impeller and connected tosaid motor, abearing supporting the shaft in desired position to permitrotation thereof, the bearing including a fixed member and a movablemember secured to-the shaft, said vmembers having cooperating taperedsurfaces, the impeller, shaft, movable bearing member and motor rotorforming a movable assembly capable of being pulled in one direction bythe thrust of the impeller, so that upon wear the assembly moves in onedirection to maintain a desired clearance between the cooperating movingin the opposite direction operating surfaces of the bearing.

8. A, pump according to claim 7 in which means are provided to move thestator. of the motor. in the same direction as therotor of the motorupon plating ofv the copon plating of the cooperating surfaces.

9. A pump according to claim 7 in which means are outlet, an impeller insaid hous- I a motor for actuating said impeller, a substantially 1tapered surfaces while provided to supply medium from the impeller tothe cooperating bearing surfaces to lubricate the same.

10. A pump according, to claim 7 in which themovable bearing membercomprises a frustum of a cone placed in a position such that its smallerarea i adjacent the housing. a v

ll. A pump according to claim 10 in which the frustum is provided withan extended portion so that the movable member has a greater length thanthe fixed member.

12. in the method of operation of an absorption-wrefrigeration systememploying a pump for circulating solution in which the solution iscapable of metal plating the bearing surfaces of the pump and in whichthe pump impeller, the impeller shaft, a tapered bearing member and themotor rotor comprise an assembly, thcmsteps which consist in actuatingthe impeller to circulate solution, supplying solution from the impellerto cooperating bearing surfaces to lubricate the same, and, as platingof the bearing surfaces occurs, automatically moving the assembly in avertical direction to prevent seizure of the bearing and failure of thepump.

13. In the method of operation of an absorption refrigeration systemincluding an absorber having a plu-' rality of tubes therein throughwhich a cooling medium is passed to cool solution exteriorly of thetubesv and employing a pump for circulating solution in which thesolution is capable of metal plating the bearing surfaces of the pump,the steps which consist in rotating the pump impeller to circulatesolution, dripping cooled solution from the tubes of the absorber uponthe pump motor to cool the same, and, as plating of the bearing surfacesoccurs, automatically moving one of the cooperating bearing surfaces toprevent seizure of the bearing and failure of the pump.

14-. In an absorption refrigeration system, the combination of anabsorber having tubes therein through which a cooling medium passes tocool solution exteriorly of the tubes, an evaporator, vapor from theevaporator flowing to the absorber to be absorbed by solution therein, acondenser, a generator, vapor from the generator flowing to thecondenser to be condensed therein, condensate from the condenser passingto the evaporator, and means to circulate solution, said meanscomprising a pump assembly placed in the absorber below said tubes andincluding a pump housing having an inlet and an outlet, an impeller insaid housing, a motor for actuating said impeller disposed above thesolution level in the absorber and in a position exposed to cooledsolution dripping from the tubes thus cooling the motor, a shaftcarrying said impeller and connected to said motor, a bearing supportingthe shaft in desired position to permit rotation thereof, the bearingincluding a fixed member, and a movable member secured to the shaft,said members having cooperating tapered surfaces, the impeller, shaft,movable bearing member and motor rotor forming a movable assemblycapable of being pulled in one direc tion by the thrust of the impeller,the assembly moving in the opposite direction upon plating of thecooperating surfaces of the bearing.

15. In an absorption refrigeration system, the combination of anabsorberthaving tubes 'th'erein'through which a cooling medium passes tocool solution exteriorly of the tubes, an evaporator, vapor from theevaporator flowing to the absorber to be absorbed-by solution there'-in, a condenser, a generator, vapor from the generator flowing 'to thecondenser to be condensedthereinjcondensate from the condenser passingto the evaporator, means to supply strong solution from the generator tothe absorber, means to supply weak solution from the absorber to thegenerator, and means to recirculate solution in the absorber, saidrecirculating means comprising a pump assembly placed in the absorberbelow said tubes including a pump housing having an inlet and an outlet,an impeller in said housing, a motor for actuating said im- 10 pellet,disposed above the solution level in the absorber movable assemblycapable of being pulled in one direcand in a position exposed to cooledsolution dripping tion by the thrust of the impeller, the assemblymoving in from the tubes, thus cooling the motor, a shaft carrying theopposite direction upon plating of the cooperating said impeller andconnected to said motor, a bearing surfaces of the bearing.

supporting the shaft in desired position to permit rota- 5 tion thereof,the bearing including a fixed member and References Cited in the file ofthis patent a movable member secured to the shaft, said members havingcooperating tapered surfaces, the impeller, shaft, UNITED STATES PATENTSmovable bearing member and motor rotor forming 2. 2,722,805 Leonard Nov.8, 1955 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No,2915 886 December 8 1959 Louis [-10 Leonard Jro It is hereby certifiedthafi error appears in the printed specification of the above numberedpatent requiring correction and that the said,Let Lers Patent shouldread as corrected below Column 2 line 68 for "power" read lower -oSigned and sealed this 5th day of July 1960,,

(SEAL) Atfiest:

KARL H. .AXLINE I ROBERT C. WATSON Attesting Officer 7 1 Cmrmissioner ofPatents

